Earth

constructive force

any natural process that builds up Earth's surface

destructive forces

Any natural process that tears down or wears away Earth's surface.

lithosphere

the rigid outer part of the earth, consisting of the crust and upper mantle.

asthenosphere

The soft layer of the mantle on which the tectonic plates move

crust

Earth's outermost layer.

mantle

the layer of the earth between the crust and the core

core

The central part of the earth below the mantle

magnetic field

a region around a magnetic material or a moving electric charge within which the force of magnetism acts

plate tectonics

The theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle

landforms

features that make up the earth's surface such as a plain, mountain, or valley

earthquake

the shaking that results from the movement of rock beneath Earth's surface

volcano

a vent or fissure in the Earth's surface through which magma and gases are expelled

magma

molten rock beneath the earth's surface

lava

liquid magma that reaches the surface

oceanic crust

earths crust located under the ocean

continental crust

The portion of the earth's crust that primarily contains granite, is less dense than oceanic crust, and is 20-50 km thick

surface waves

seismic waves that travel along the Earth's surface

primary waves

waves that travel outward from an Earthquake's focus and cause particles in rocks to move back and forth in the same direction the wave is moving

secondary waves

waves that travel outward from an earthquake's focus and move through Earth by causing particles in rocks to vibrate at right angles to the direction of the wave

seismic

relating to or caused by an earthquake

mid-ocean ridge

An undersea mountain chain where new ocean floor is produced; a divergent plate boundary.

seafloor spreading

The process that creates new sea floor as plates move away from each other at the mid-ocean ridges

plate boundaries

the edges of tectonic plates

continental drift

the hypothesis that the continents slowly move across Earth's surface

divergent

going in different directions

convergent

coming together

transform boundary

a plate boundary where two plates move past each other in opposite directions

subduction

one plate going under another plate

crystallization

The process by which atoms are arranged to form a material with a crystal structure

decay

to break down or wear away

weathering

The breaking down of rocks and other materials on the Earth's surface.

clay

the finest soil, made up of particles that are less than 0.002 mm in diameter.

loam

A mixture of gravel, sand, silt, clay, and organic matter

humus

material formed from decaying leaves and other organic matter

sand

the coarsest soil, with particles 0.05,2.0 mm in diameter.

silt

A mixture of rich soil and tiny rocks

mineral

a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition

sedimentary

A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together

igneous

a type of rock that forms from the cooling of molten rock at or below the surface

metamorphic

A type of rock that forms from an existing rock that is changed by heat, pressure, or chemical reactions.

pedosphere

The outermost layer of the Earth that is composed of soil.

vegetative cover

grasses, trees, shrubs, and any other plants that help to hold the soil in place

agriculture

farming

contour plowing

plowing fields along the curves of a slope to prevent soil loss

conservation plowing

farmers disturb the soil and its plant cover as little as possible

crop rotation

The practice of rotating use of different fields from crop to crop each year, to avoid exhausting the soil.

vector

carrier (of disease, for example)

remote sensing

The acquisition of data about Earth's surface from a satellite orbiting the planet or other long-distance methods.

erosion

Processes by which rock, sand, and soil are broken down and carried away (i.e. weathering, glaciation)

stewardship

Looking after something so it can be passed on to the next generation